A03 - Ecosystem-scale assessment of the full greenhouse gas and energy balance of an oil palm plantation in Sumatra (Indonesia)

Current land transformation in Indonesia resulted in a rapid expansion of oil palm plantation. While carbon dioxide (CO₂) uptake of mature oil palm is typically large, hardly any information is available on the complete greenhouse gas (GHG) and energy balance of oil palm plantation, which is however necessary to quantify correctly the overall climate impact of oil palm plantations. Particularly, nitrous oxide (N₂O) is of relevance for commercial oil palm plantations as its production is closely linked to fertiliser application, and because of the large amounts of nitrogen fertilizer typically applied in these plantations. In this project, we will build on our successful installation of a climate tower in an oil palm plantation in CRC phase 1, where CO₂, H₂O, and methane (CH₄) fluxes are currently being measured, and assess now the full GHG balance, including N₂O fluxes, using the eddy covariance technique and meteorological measurements (WP1). Fluxes of CO₂, N₂O and CH₄ are expected to vary in space and time in relation on management practise as well as soil and plant water status. Also, N₂O and CH₄ are typically intermittent thus requiring continuous measurements to understand the link to rapid changes in soil and plant water and fertilizer application. We will apply a spatially resolved footprint model to link the continuously measured GHG fluxes at the climate tower to spatial variability in the oil palm plantation. We will also investigate the response of GHG fluxes to specific meteorological events affecting water availability (WP2). Furthermore, microclimate within canopies of different land-use types directly influences ecological and biogeochemical processes. Thus, we compare the microclimate of different land-use types (forest, rubber and oil palm plantation) based on the Z02 meteorological station network and identify its relation to canopy structure i.e. canopy openness (WP3).